Wind Turbine Buyers Guide - RENEW Wisconsin

wind turbinesImporters:Lake Michigan Wind & Sun • 920-743-0456 • www.windandsun.comSolar Wind Works • 877-682-4503 • www.solarwindworks.comProven WT 0.6Rotor diameter: 8.4 feet (2.6 m)Swept area: 55 square feet (5.1 m 2 )Rated rpm: 500Predicted energy output at average wind speeds: 42 KWH permonth at 8 mph; 83 at 10 mph; 124 at 12 mphApplication: Batteryless grid-tie; 12, 24, 48 VDC battery chargingPrice (MSRP): $4,870 without controller or inverterWarranty: 2 years; extended warranty availableProven WT 2.5Rotor diameter: 11.1 feet (3.4 m)Swept area: 97 square feet (9 m 2 )Rated rpm: 300Predicted energy output at average wind speeds: 167 KWH permonth at 8 mph; 293 at 10 mph; 417 at 12 mphApplication: Batteryless grid-tie; 24, 48 VDC battery chargingPrice (MSRP): $9,650 without controller or inverterWarranty: 2 years; extended warranty availableProven WT 6Rotor diameter: 18 feet (5.5 m)Swept area: 254 square feet (23.6 m 2 )Rated rpm: 200Predicted energy output at average wind speeds: 417 KWH permonth at 8 mph; 667 at 10 mph; 1,083 at 12 mphApplication: Batteryless grid-tie or 48 VDC battery chargingPrice (MSRP): $20,500 without controller or inverterWarranty: 2 years; extended warranty availableProven WT 15Rotor diameter: 29.5 feet (9 m)Swept area: 683 square feet (63.5 m 2 )Rated rpm: 150Predicted energy output at average wind speeds: 777 KWH permonth at 8 mph; 1,451 at 10 mph; 3,080 at 12 mphApplication: Batteryless grid-tie or 48 VDC battery chargingPrice (MSRP): $39,340 without controller or inverterWarranty: 2 years; extended warranty availableProven WT 0.6 Proven WT 2.5 Proven WT 6 Proven WT 15Other ConsiderationsA turbine’s revolutions per minute (rpm) at its rated windspeed can give you some idea of the relative aerodynamicsound of the machine, and also speaks to longevity. Slowerturningwind turbines tend to be quieter and last longer.High rpm machines wear out components, such as bearings,much faster. In addition, the faster blades move through theair, the greater the possibility that they will waste some ofthat energy as sound from the blades.Some manufacturers make only battery-chargingmachines, and may offer a variety of turbine voltages. Othersproduce machines intended to connect to grid-synchronousinverters without batteries. One machine even includes aninverter integrated with the turbine itself. Make sure you’rebuying a machine that is appropriate for your intended use.Make Your ChoiceTrying to keep an inexpensive wind generator running canbe an uphill battle that you’ll soon tire of. But expect to paymore for a better machine—it’s a tough job to design andmanufacture a long-lasting, small-scale wind generator.The bottom line: Buy a turbine that has a very good trackrecord and a good warranty—five years is preferable butnot always available in the small wind industry. A warrantyis one indication of the manufacturer’s confidence in theirproduct, and their intention to stand behind it.Real-world reports from users carry even more weightthan a warranty, so search for people who own the modelof turbine you’re considering buying, and get the straightscoop from them about performance, durability, reliability,and maintenance issues.Note that a number of the wind turbines listed here arerelatively new introductions with not very much customerrun-time in North America. These turbines include theARE, Eoltec, Kestrel, and Skystream. We recommendthat you contact either your local wind turbine installer,or the manufacturers or importers and find out howmany of these machines are actually operating in North38home power 119 / june & july 2007